Re: [APML] Film Creep

["Steve Walters" <s-walters@comcast.net>]

Hi Jon,

Thanks for the suggestion but it already has a vac back. I had problems with
the original vac pump that allowed the film to lift up during exposures but
I replaced it and solved that problem.

In any case, a vac back will not keep the film from changing dimensions due
to temp or humidity levels. It can only keep it flat.

Steve...

----- Original Message ----- 
From: "Jon Kolb" <jkolb@datawest.net>
To: "'Discussion of Film Astrophotography'" <astro-photo@seds.org>
Sent: Sunday, September 28, 2003 12:15 AM
Subject: RE: [APML] Film Creep


> Hi Steve,
>
> > Any suggestions on solving this problem would be very welcome.
>
> I haven't tried to verify your calculations, but I will say that going
> with a vacuum back may solve the problem.  I bought the Hutech version
> that replaces the standard Pentax 67 back, and although I thought it was
> a little pricey, it sure helped cure some of my shots of the same
> symptoms you describe.  Understand, however, that I have pretty dry
> conditions to begin with - my meter said the dewpoint was -3.5F Friday
> night with an ambient temp of 28F.  Still my camera sweeps close to the
> ground with my long refractor, down where it's wetter, and the vacuum
> back did make a very noticeable difference once I started using it.
>
> Sincerely,
> Jon Kolb
> Adventures in Astrophotography
> http://home.datawest.net/jkolb/
> jkolb@datawest.net
>
>
>
> _______________________________________________
> Astro-Photo mailing list
> Astro-Photo@seds.org
> http://seds.org/mailman/listinfo/astro-photo

_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo